In order to decorate an element or component of a timepiece or piece of jewellery, enamelling may be performed on a surface of the component after creating a set of cells or partitions on the component. This may be hot enamelling. This conventional technique known as “cloisonné” is one of numerous enamelling techniques, which include amongst others: “grisaille”, dry applique, painting on enamel, “champlevé”, “basse-taille”, “plique-à-jour”, relief enamelling, “paillonné”, to name the main techniques.
The principle of this traditional decorative technique consists in manually creating a design formed of metal wire partition walls, then filling the partitions with successive layers of transparent or opaque enamels on a metal or ceramic support. The raw materials of the vitreous substance known as enamel are mainly silica, in the form of very pure sand, feldspars, pegmatites, chalk, lime and sometimes kaolin, associated with metal compounds to give the enamel its colour. This substance deposited on a surface of a component is fired until it fuses and adheres to the metal or ceramic component. The process of creating the decoration by various manual steps is long and cannot be reproduced in an identical manner from one component to the next, which is a drawback.
In the case of the “cloisonné” or partitioned technique, there is generally a significant number of steps required to create the decorated element. This requires drawing the design directly on paper or on a computer before creating the decorative patterns by hand, notably with a metal wire placed on the drawing as a base. The reproduction of the drawing on a metal or ceramic or ceramo-metallic support is generally achieved by hand engraving, machine engraving or freehand engraving. The support can then be enamelled with an enamel layer which may or may not be transparent. The patterns of the decoration are then placed on the support and secured to form the cells or partition walls, which are made level. A filler material, such as enamel, is subsequently inserted in the partitions and normally the enamelled support must also be fired. A polishing operation may also be provided when the enamelled component is removed from the furnace. Since this method of producing a decorated element requires a very large number of steps, this constitutes a drawback for making such a decorated element.
Reference may be made in this regard to EP Patent No. 2 380 864 B1, which describes a method for manufacturing a ceramic element, which is inlaid with at least one metallic decoration. First of all an etch is made in the ceramic material by means of a laser beam to obtain one or more hollows. Next, in each hollow, a metal layer is deposited by vapour phase deposition and autocatalysis to form the adhesion layer. Thereafter, a decorative layer is electroplated on the adhesion layer to finalise the decoration of the element. It is complicated to fill each hollow made in the ceramic material with the metallic layers to form the decorated element, which is a drawback. Further, decoration exclusively by vapour phase deposition of a metallic layer cannot produce decorative layers of sufficient thickness.
CH Patent Application No. 707 533 A2 describes a method for manufacturing a watch dial decorated with embroidery. First of all, a decal etch is made in a cloth canvas or embroidery. Once the overlay or copy sheet is pierced with the desired design, a powder is spread over the overlay. The design is then printed on the canvas to highlight the design for the embroidery operation, which follows this printing step. Once the embroidery is finished, the decorated canvas is bonded to a support, such as a watch dial. This method also includes a very large number of steps for decorating the watch dial, which is a drawback. Further, it is not possible to create a decoration of complex shape with this method and the bonding of the decoration is generally not reliable in the long-term.
US Patent Application Nos 2011/0203934 A1 and 2011/0303546 A1 describe a method for fabricating metal microstructures. To obtain such metal microstructures, a heterogeneous LIGA method is used. First of all, a metal adhesion layer must be deposited on a base substrate, and a photosensitive resin layer is structured by photolithography. A metal design is then produced, in the portions removed from the resin layer, by galvanic growth on the metal adhesion layer. Finally, the resin layer is removed, as is the base substrate, to obtain said metal microstructure. Since the metal microstructure is obtained by a LIGA method with galvanic growth, this means it is impossible to produce a decorated element rapidly and easily, which is a drawback.
EP Patent Application No. 2 316 299 A1 describes a timepiece or piece of jewellery and the method of fabricating the same. The piece includes a metal base structure, which is provided with a relief decoration, and with an elastomer layer deposited on a surface of the structure by means of an adhesion layer. The decorative design is obtained by milling or chemical etching or laser or stamping, but it cannot rapidly and easily provide a precise decoration of complex shape, which is a drawback.